To confirm if a colorless liquid is pure water, you can measure its boiling and freezing points under standard atmospheric pressure. If the boiling point is 100°C and the freezing point is 0°C, then it’s likely pure water. Additionally, evaporating the liquid and observing if any residue remains can indicate the presence of impurities.
Here’s a more detailed breakdown:
1. Boiling Point:
Heat the liquid and observe its temperature when it starts boiling. Pure water should boil at 100°C (373 K) under standard atmospheric pressure.
2. Freezing Point:
Cool the liquid and observe its temperature when it starts freezing. Pure water should freeze at 0°C (273 K) under standard atmospheric pressure.
3. Evaporation:
Evaporate the liquid (e.g., by heating it in a dish). If any residue remains after evaporation, it suggests the presence of impurities in the liquid.
4. pH Test:
Using litmus paper, you can test the pH of the liquid. Pure water is neutral and will not change the color of litmus paper.